Biohydrogen is a versatile future energy carrier from renewable sources. Hydrogenase enzymes can be used in microbial fuel cells to oxidize dihydrogen and generate electricity. These enzymes can be immobilized on a graphite electrode surface and generate an electric current in a microbial fuel cell.
Brownian Dynamics simulations have been used to efficiently sample the protein diffusion and orientation at the graphite surface and identify amino acid residues which mediate the flow of electrons from the distal [FeS]-cluster to the electrode. The rate of electron transfer (ET) at the anodic side between the [NiFe]-hydrogenase enzyme distal iron–sulfur cluster and the electrode surface can fully be described by Marcus theory. All parameters for the Marcus equation are accessible from Density Functional Theory (DFT) calculations.